使用d3.js的时候,如何用zoom translate scale限制拖拽范围
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红色代表需要改写的代码
1.添加定义图像大小和容器的大小及坐标
d3.behavior.zoom = function () { var moveCanvas={ width: 0, height: 0, cx:0,cy:0,cwidth:0,cheight:0 }; var view = { x: 0, y: 0, k: 1 }, translate0, center0, center, size = [ 960, 500 ], scaleExtent = d3_behavior_zoomInfinity, duration = 250, zooming = 0, mousedown = "mousedown.zoom", mousemove = "mousemove.zoom", mouseup = "mouseup.zoom", mousewheelTimer, touchstart = "touchstart.zoom", touchtime, event = d3_eventDispatch(zoom, "zoomstart", "zoom", "zoomend"), x0, x1, y0, y1; if (!d3_behavior_zoomWheel) { d3_behavior_zoomWheel = "onwheel" in d3_document ? (d3_behavior_zoomDelta = function() { return -d3.event.deltaY * (d3.event.deltaMode ? 120 : 1); }, "wheel") : "onmousewheel" in d3_document ? (d3_behavior_zoomDelta = function() { return d3.event.wheelDelta; }, "mousewheel") : (d3_behavior_zoomDelta = function() { return -d3.event.detail; }, "MozMousePixelScroll"); }
2.添加定义设置参数方法
zoom.y = function(z) { if (!arguments.length) return y1; y1 = z; y0 = z.copy(); view = { x: 0, y: 0, k: 1 }; return zoom; }; zoom.moveCanvas = function (_) { if (!arguments.length) return [moveCanvas.width, moveCanvas.height, moveCanvas.cx, moveCanvas.cy, moveCanvas.cwidth, moveCanvas.cheight]; moveCanvas = { width: +_[0],//图像宽度 height: +_[1],//图像高度 cx: +_[2],//容器坐标x cy: +_[3],//容器坐标y cwidth: +_[4],//容器宽度 cheight: +_[5],//容器高度 }; return zoom; };
3.重写translateTo方法
function scaleTo(s) { view.k = Math.max(scaleExtent[0], Math.min(scaleExtent[1], s)); } function translateTo(p, l) { l = point(l); view.x += p[0] - l[0]; view.y += p[1] - l[1]; var minx = moveCanvas.cx - view.k * moveCanvas.width / 2;//图像的一半 var maxx = moveCanvas.cx + moveCanvas.cwidth - moveCanvas.width / 2*view.k; var miny = moveCanvas.cy - view.k * moveCanvas.height / 2;//图像的一半 var maxy = moveCanvas.cy + moveCanvas.cheight - moveCanvas.height / 2*view.k; if (view.x < minx) view.x = minx; if (view.y < miny) view.y = miny; if (view.x > maxx) view.x = maxx; if (view.y > maxy) view.y = maxy; }
4.页面调用
var zoom = d3.behavior.zoom() .scaleExtent([0.5, 2]) .moveCanvas([svgWidth,svgHeight,0,0,divWidth,divHeight]) .on("zoom", function (d) { sval = d3.event.scale; console.info("transform"); gMap.attr("transform", "translate(" + d3.event.translate + ")" + "scale(" + d3.event.scale + ")") });
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